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Betaine
Kinds of Betaine Selected AbstractsBetaine Adducts of N-Heterocyclic Carbenes: Synthesis, Properties, and ReactivityEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2009Lionel Delaude Abstract N-Heterocyclic carbenes (NHCs) form stable zwitterionicadducts with a range of heteroallenes, ketenes, and allenes. Although the first representatives of this class of inner salts were first investigated as far back as the 1960s, they have enjoyed a sustained interest from the chemical community over the years. Depending on the nature of their anionic moiety, NHC betaines display a very broad palette of reactivities and have found applications in various fields of organic synthesis and catalysis. In this Microreview, the synthesis, properties, and reactivity of NHC betaines are surveyed. The NHCs under consideration include ylidenes derived from imidazole, benzimidazole, imidazoline, thiazole, or triazole, and the heteroallenes investigated so far are carbon dioxide, carbon disulfide, isocyanates, isothiocyanates, and their selenium analogues. A historical background is provided for each type of adduct under consideration, but emphasis is placed mainly on developments that have appeared in the literature within the past few years. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Mechanisms of protection by the betaine-homocysteine methyltransferase/betaine system in HepG2 cells and primary mouse hepatocytes,HEPATOLOGY, Issue 5 2007Cheng Ji Betaine-homocysteine methyltransferase (BHMT) regulates homocysteine levels in the liver. We previously reported that the alteration of BHMT is associated with alcoholic liver steatosis and injury. In this study, we tested whether BHMT protects hepatocytes from homocysteine-induced injury and lipid accumulation. Both BHMT transfectants of HepG2 cells and primary mouse hepatocytes with suppressed BHMT were generated. Comparisons were made between the cell models with respect to their response to homocysteine treatments. Homocysteine metabolism was impaired in HepG2 cells, and the expression of BHMT in HepG2 cells ameliorated the impairment and stabilized the levels of intracellular homocysteine after the addition of exogenous homocysteine. BHMT expression inhibited homocysteine-induced glucose-regulated protein 78 (GRP78) and C/EBP-homologous protein (CHOP) and homocysteine-induced cell death. A betaine treatment protected primary mouse hepatocytes from a homocysteine-induced increase in GRP78 and cell death but not a tunicamycin-induced increase. Homocysteine induced greater CHOP expression (2.7-fold) in BHMT small interfering RNA (siRNA),transfected cells than in a control (1.9-fold). Homocysteine-induced cell death was increased by 40% in the siRNA-treated cells in comparison with the control. Apolipoprotein B (apoB) expression was higher and triglycerides and cholesterol were lower in HepG2 expressing BHMT. In primary mouse hepatocytes, homocysteine induced the accumulation of triglycerides and cholesterol, which was reduced in the presence of betaine. Betaine partially reduced homocysteine-induced sterol regulatory element binding protein 1 expression in HepG2 cells and increased S-adenosylmethionine in primary mouse hepatocytes. Conclusion: The BHMT/betaine system directly protects hepatocytes from homocysteine-induced injury but not tunicamycin-induced injury, including an endoplasmic reticulum stress response, lipid accumulation, and cell death. This system also exhibits a more generalized effect on liver lipids by inducing ApoB expression and increasing S-adenosylmethionine/S-adenosylhomocysteine. (HEPATOLOGY 2007.) [source] Ectoines as compatible solutes and carbon and energy sources for the halophilic bacterium Chromohalobacter salexigensJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2006C. Vargas Abstract Aims:, To investigate the catabolism of ectoine and hydroxyectoine, which are the major compatible solutes synthesized by Chromohalobacter salexigens. Methods and Results:, Growth curves performed in M63 minimal medium with low (0·75 mol l,1 NaCl), optimal (1·5 mol l,1 NaCl) or high (2·5 mol l,1 NaCl) salinity revealed that betaine and ectoines were used as substrate for growth at optimal and high salt. Ectoine transport was maximal at optimal salinity, and showed 3- and 1·5-fold lower values at low and high salinity respectively. The salt-sensitive ectA mutant CHR62 showed an ectoine transport rate 6·8-fold higher than that of the wild type. Incubation of C. salexigens in a mixture of glucose and ectoine resulted in a biphasic growth pattern. However, CO2 production due to ectoine catabolism was lower, but not completely abolished, in the presence of glucose. When used as the sole carbon source, glycine betaine effectively inhibited ectoine and hydroxyectoine synthesis at any salinity. Conclusions:, The catabolic pathways for ectoine and hydroxyectoine in C. salexigens operate at optimal and high (although less efficiently) salinity. Endogenous ectoine(s) may repress its own transport. Ectoine utilization was only partially repressed by glucose. Betaine, when used as carbon source, suppresses synthesis of ectoines even under high osmolarity conditions. Significance and Impact of the Study:, This study is a previous step to the subsequent isolation and manipulation of the catabolic genes, so as to generate strains with enhanced production of ectoine and hydroxyectoine. [source] Betaine Protects Chronic Alcohol and ,-3 PUFA-Mediated Down-Regulations of PON1 Gene, Serum PON1 and Homocysteine Thiolactonase Activities With Restoration of Liver GSHALCOHOLISM, Issue 3 2010Ravi Varatharajalu Background:, Paraoxonase (PON1) is an antioxidant enzyme that prevents LDL oxidation as well as detoxifies homocysteine thiolactone (HCTL), both of which can cause atherosclerosis. Chronic alcohol (ETOH) and high ,-3 polyunsaturated fatty acids (,-3 PUFA) consumption may affect PON1 status presumably via reactive oxygen species by depleting liver glutathione (GSH), whereas betaine may counter their effects. Therefore, we investigated the influence of ETOH, ,-3 PUFA, and betaine on liver GSH, PON1 expression, lipid score, as well as serum PON1 and HCTLase activities. Methods:, Experimental rats belonging to various dietary groups were pair-fed with Lieber-DeCarli low (2.8% the dietary calories as ,3-fatty acids) and high (13.8% the dietary calories as ,3-fatty acids) menhaden fish alcohol-liquid diets with and without betaine (10 g/l diet) for 8 weeks after which liver PON1 mRNA, GSH, lipid score, and serum PON1, HCTLase, and ALT activities were measured. Results:, High ,-3 PUFA decreased liver PON1 mRNA expression, serum PON1, and HCTLase activity by 23% (p < 0.01), 20% (p < 0.05), and 28% (p < 0.05), respectively compared to the low ,-3 PUFA group. ETOH decreased PON1 mRNA expression by 25 and 30% (p < 0.01) with concomitant 27% (p < 0.05) and 38% (p < 0.01), decrease in liver GSH levels in low and high ,-3 PUFA groups, respectively. Correspondingly, serum PON1 activity decreased by 23% (p < 0.05) and 58% (p < 0.01) while serum HCTLase activity decreased by 25% (p < 0.05) and 59% (p < 0.01) in the low and high ,-3 PUFA ETOH groups, respectively. Betaine restored liver PON1 mRNA expressions in low and high ,-3 PUFA ETOH groups with parallel restorations of PON1 activity and liver GSH. Concomitantly, betaine reduced hepatosteatosis accompanied by alleviation of liver injury caused by chronic alcohol and high ,-3 PUFA. Conclusions:, Based on these results, we conclude that dietary betaine not only atheroprotective by restoring liver GSH that quenches free radicals, but also may alleviate liver injury by reducing hepatosteatosis. [source] Betaine and homocysteine concentrations in foodsPEDIATRICS INTERNATIONAL, Issue 4 2002Akiko Sakamoto Abstract Background: Betaine (Bet) supplementation is an effective strategy for dietary treatment of homocystinuria. However,previous reports on diet therapy have only examined methionine (Met) and cystine concentrations, but not those of Bet and homocysteine(Hcy) in food items. We set up a hypothesis that there are some food items, which contain a small amount of Met, but a great amountof Hcy and Bet. Methods: We measured Bet and Hcy concentrations in 58 food items, which were regarded as containing low Met. Results: Products of wheat flour are rich in Bet. The amount of Bet in food items investigated in this study is muchsmaller than the dose used to treat homocystinuria patients. Vegetables contained little Hcy, however sprouted beans and sprouted alfalfaseeds contained ample Hcy. Conclusion: Patients with homocystinuria do not have to be too concerned about Hcy in food items because the amountis small. Therefore, we encourage homocystinuria patients to continue a low Met diet therapy without anxiety of Hcy and Bet, and if necessary,Bet will be supplemented. [source] Crystallization and preliminary X-ray study of recombinant betaine,homocysteine S -methyltransferase from rat liverACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2002Beatriz González Betaine,homocysteine S -methyltransferase is one of the three enzymes involved in homocysteine catabolism. It uses betaine as the methyl donor to convert homocysteine into methionine, also producing dimethylglycine. Recombinant BHMT from rat liver was crystallized by the vapour-diffusion method in both native and seleniomethionyl-labelled forms. Crystals belong to space group P21, with unit-cell parameters a = 57.8, b = 149.3, c = 96.2,Å, , = 92.9°. Data from native, seleniomethionine-labelled and two heavy-atom derivatives were collected using synchrotron sources. Self-rotation function and sedimentation-velocity experiments suggest that the enzyme is tetrameric with 222 symmetry. [source] Crystallization and preliminary X-ray crystallographic studies of recombinant human betaine,homocysteine S-methyltransferaseACTA CRYSTALLOGRAPHICA SECTION D, Issue 3 2001Nandita Bose Betaine,homocysteine S-methyltransferase (BHMT) catalyzes a reaction essential for regulation of methionine and homocysteine metabolism and the catabolism of choline in mammalian tissues. Human recombinant BHMT (MW = 45,kDa) has been crystallized by the hanging-drop vapor-diffusion method at 294,K using ethylene glycol as the precipitant. The crystals belong to the monoclinic space group C2, with unit-cell parameters a = 109.190, b = 91.319, c = 88.661,Å, , = 122.044°, and diffract to 2.9,Å resolution on a local rotating-anode X-ray source. Rotation-function analysis and the Matthews coefficient, VM = 2.46,Å3,Da,1, are consistent with a dimer in the asymmetric unit, suggesting that the active enzyme is a tetramer with 222 symmetry. [source] Osmoprotective Effect of Glycine Betaine on Thrombopoietin Production in Hyperosmotic Chinese Hamster Ovary Cell Culture: Clonal VariationsBIOTECHNOLOGY PROGRESS, Issue 5 2000Tae Kyung Kim When 23 recombinant Chinese hamster ovary (rCHO) cell clones were cultivated in hyperosmolar medium resulting from NaCl addition (533 mOsm/kg), their specific thrombopoietin (TPO) productivity (qTPO) was increased. However, due to depressed cell growth at elevated osmolality, no enhancement in the maximum TPO titer was made in batch cultures of all 23 clones. To test the feasibility of using glycine betaine, known as a strong osmoprotective compound, for improved TPO production in hyperosmotic rCHO cell cultures, hyperosmotic batch cultures of 23 clones were performed in the presence of 15 mM glycine betaine. Glycine betaine was found to have a strong osmoprotective effect on all 23 clones. Inclusion of 15 mM glycine betaine in hyperosmolar medium enabled 22 clones to grow at 542 mOsm/kg, where most clones could not grow in the absence of glycine betaine, but at a cost of reduced qTPO. However, the relative decrease in qTPO varied significantly among clones. Thus, efficacy of the simultaneous use of hyperosmotic pressure and glycine betaine as a means to improve foreign protein production was variable among clones. Six out of 23 clones displayed more than a 40% increase in the maximum TPO titer in the hyperosmolar medium containing glycine betaine, compared with that in the standard medium with a physiological osmolality. Taken together, the results obtained here emphasize the importance of selection of clones for the successful use of hyperosmotic pressure and glycine betaine as an economical means to improve TPO production. [source] ChemInform Abstract: Flexible Synthesis, Structural Determination, and Synthetic Application of a New C1 -Symmetric Chiral Ammonium Betaine.CHEMINFORM, Issue 19 2010Daisuke Uraguchi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] [6 + 3] Cycloaddition of Fulvenes with 3-Oxidopyrylium Betaine: A Novel Methodology for the Synthesis of Fused Cyclooctanoid Natural Products.CHEMINFORM, Issue 43 2005K. V. Radhakrishnan Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: A Convenient Method for the Alkylation of Sulfamides Using Alkyl Bromides and Mitsunobu Betaine.CHEMINFORM, Issue 18 2001Jean-Yves Winum Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Nucleophilic Carbenes and Pseudo-Cross-Conjugated Mesomeric Betaines of Indazole Starting from Analogues of the Alkaloid-Betaine NigellicineEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 10 2005Andreas Schmidt Abstract The alkaloid Nigellicine possesses the indazolium-3-carboxylate ring system as electronically relevant partial structure which represents a member of the class of pseudo-cross-conjugated mesomeric betaines. Indazolium-3-carboxylate, prepared starting from indazole-3-carboxylic acid by an esterification,methylation,saponification sequence, can be converted into the isoconjugated phenyl- and 4-(nitrophenyl)amidates and the thiocarboxylate as additional examples of pseudo-cross-conjugated systems. In accordance with results of ab initio calculations decarboxylation of indazolium-3-carboxylate with formation of the nucleophilic carbene indazol-3-ylidene begins at approximately 40 °C as evidenced by temperature-dependent NMR spectroscopy. The carbene can be trapped with protons as indazolium salts, and carbon dioxide which reconstitutes the pseudo-cross-conjugated mesomeric betaine. According to the calculations, the carbene adopts a singlet ground state. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Chiral Ammonium Betaines as Ionic Nucleophilic Catalysts,ANGEWANDTE CHEMIE, Issue 32 2010Daisuke Uraguchi Dr. Ungeahnte Qualitäten: Das chirale Ammoniumbetain 1 war als ionischer nucleophiler Katalysator in der asymmetrischen Steglich-Umlagerung erfolgreich. Die Umsetzung ergab rekordverdächtige Enantioselektivitäten und war auf vielfältige Substrate anwendbar. M.S. = Molekularsieb, Troc = 2,2,2-Trichlorethoxycarbonyl. [source] ChemInform Abstract: Chiral Ammonium Betaines: A Bifunctional Organic Base Catalyst for Asymmetric Mannich-Type Reaction of ,-Nitrocarboxylates.CHEMINFORM, Issue 1 2009Daisuke Uraguchi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Bacterioplankton assemblages transforming dissolved organic compounds in coastal seawaterENVIRONMENTAL MICROBIOLOGY, Issue 8 2007Xiaozhen Mou Summary To characterize bacterioplankton functional assemblages that transform specific components of the coastal seawater dissolved organic carbon (DOC) pool, bromodeoxyuridine (BrdU) was used to label the bacterioplankton cells that were active following addition of single-DOC model compounds: two organic osmolytes [dimethylsulfoniopropionate (DMSP) and glycine betaine (GlyB)] and two aromatic monomers [para -hydroxybenzoic acid (pHBA) and vanillic acid (VanA)]. Bacterial populations were analysed based on in situ fluorescent immunodetection of BrdU incorporation followed by fluorescence-activated cell sorting (FACS). Sorted cells were then characterized by 16S rDNA-based analysis. Populations with high BrdU incorporation level (HI) developed within 8 h of introduction of 100 nM model compound. Terminal restriction fragment length polymorphisms (T-RFLP) analysis indicated that the HI populations in all four amendments were composed of bacteria from the same major taxa (phylum and subphylum levels), but the relative abundance of each differed. High-resolution clone libraries (each containing ,200 clones) showed that the HI populations in the GlyB and VanA amendments consisted of both metabolic generalists and specialists within the , -Proteobacteria (mainly members of the Roseobacter clade), , -Proteobacteria and , -Proteobacteria (mainly members of Altermonadaceae, Chromatiaceae, Oceanospirillaceae and Pseudomonadaceae). The presence of members of OM60/241, OM185, SAR11, SAR86 and SAR116 in the HI populations indicated that members of these groups can assimilate the model DOC compounds, providing some of the first glimpses into heterotrophy by members of these poorly understood environmental clusters. [source] Nucleophilic Carbenes and Pseudo-Cross-Conjugated Mesomeric Betaines of Indazole Starting from Analogues of the Alkaloid-Betaine NigellicineEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 10 2005Andreas Schmidt Abstract The alkaloid Nigellicine possesses the indazolium-3-carboxylate ring system as electronically relevant partial structure which represents a member of the class of pseudo-cross-conjugated mesomeric betaines. Indazolium-3-carboxylate, prepared starting from indazole-3-carboxylic acid by an esterification,methylation,saponification sequence, can be converted into the isoconjugated phenyl- and 4-(nitrophenyl)amidates and the thiocarboxylate as additional examples of pseudo-cross-conjugated systems. In accordance with results of ab initio calculations decarboxylation of indazolium-3-carboxylate with formation of the nucleophilic carbene indazol-3-ylidene begins at approximately 40 °C as evidenced by temperature-dependent NMR spectroscopy. The carbene can be trapped with protons as indazolium salts, and carbon dioxide which reconstitutes the pseudo-cross-conjugated mesomeric betaine. According to the calculations, the carbene adopts a singlet ground state. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Propyne Iminium Salts and Phosphorus(III) Nucleophiles: Synthesis of (3-Morpholinoallenyl)phosphanes and -phosphane Oxides or 1-(Morpholinopropargyl)phosphanes and -phosphonatesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 11 2003Martin Reisser Abstract Treatment of 4-(1,3-diphenyl-l-propynylidene)morpholinium triflate (1a) with the neutral phosphorus nucleophiles Me3Si,PPh2, Me3Si,P(Ph)C5H11, and Me3SiO,PPh2 affords (3-morpholinoallenyl)phosphanes 4 and 5 and (3-morpholinoallenyl)phosphane oxide 11, respectively. In contrast to these conjugate addition reactions at the ambident propyne iminium moiety of 1a, nucleophilic attack by Me3Si,PEt2 and Me3SiO,P(OEt)2 takes place at the iminium function and gives (1-morpholinopropargyl)phosphane 6 and (1-morpholinopropargyl)phosphonate 12, respectively. Propyne iminium salt 1b reacts with Me3Si,PPh2 to form (3-morpholino-1,3-butadienyl)phosphane oxide 8. The bis(donor)-substituted allene 4 is transformed by oxidation of the phosphorus substituent into the push-pull substituted allenylphosphane oxide 11. Treatment of allene 4 with elemental sulfur results in the formation of betaine 16, which undergoes [3+2] cycloaddition reactions with acetylenic esters to afford 5-benzylidene-4,5-dihydrothiophenes 17 and 18. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Mechanisms of protection by the betaine-homocysteine methyltransferase/betaine system in HepG2 cells and primary mouse hepatocytes,HEPATOLOGY, Issue 5 2007Cheng Ji Betaine-homocysteine methyltransferase (BHMT) regulates homocysteine levels in the liver. We previously reported that the alteration of BHMT is associated with alcoholic liver steatosis and injury. In this study, we tested whether BHMT protects hepatocytes from homocysteine-induced injury and lipid accumulation. Both BHMT transfectants of HepG2 cells and primary mouse hepatocytes with suppressed BHMT were generated. Comparisons were made between the cell models with respect to their response to homocysteine treatments. Homocysteine metabolism was impaired in HepG2 cells, and the expression of BHMT in HepG2 cells ameliorated the impairment and stabilized the levels of intracellular homocysteine after the addition of exogenous homocysteine. BHMT expression inhibited homocysteine-induced glucose-regulated protein 78 (GRP78) and C/EBP-homologous protein (CHOP) and homocysteine-induced cell death. A betaine treatment protected primary mouse hepatocytes from a homocysteine-induced increase in GRP78 and cell death but not a tunicamycin-induced increase. Homocysteine induced greater CHOP expression (2.7-fold) in BHMT small interfering RNA (siRNA),transfected cells than in a control (1.9-fold). Homocysteine-induced cell death was increased by 40% in the siRNA-treated cells in comparison with the control. Apolipoprotein B (apoB) expression was higher and triglycerides and cholesterol were lower in HepG2 expressing BHMT. In primary mouse hepatocytes, homocysteine induced the accumulation of triglycerides and cholesterol, which was reduced in the presence of betaine. Betaine partially reduced homocysteine-induced sterol regulatory element binding protein 1 expression in HepG2 cells and increased S-adenosylmethionine in primary mouse hepatocytes. Conclusion: The BHMT/betaine system directly protects hepatocytes from homocysteine-induced injury but not tunicamycin-induced injury, including an endoplasmic reticulum stress response, lipid accumulation, and cell death. This system also exhibits a more generalized effect on liver lipids by inducing ApoB expression and increasing S-adenosylmethionine/S-adenosylhomocysteine. (HEPATOLOGY 2007.) [source] Vehicle effects on skin sensitizing potency of four chemicals: assessment using the local lymph node assayINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 2 2001Z M Wright Synopsis The murine local lymph node assay (LLNA) can be used to determine the relative skin sensitizing potency of chemicals via interpolation of the quantitative dose response data generated. Using this approach we have demonstrated previously that the vehicle matrix in which a chemical allergen is encountered on the skin can have a significant influence on sensitizing potency. Estimates of relative potency are calculated from LLNA dose responses as a function of the mathematically derived EC3 value, this being the concentration estimated to induce a stimulation index (SI) of 3. To investigate further the influence of application vehicle on sensitizing potency, the LLNA has been used to examine the activity of four recognized human contact allergens: isoeugenol and cinnamic aldehyde, two fragrance chemicals; 3-dimethylaminopropylamine (a sensitizing impurity of cocamidopropyl betaine, a surfactant used in shower gel) and dibromodicyanobutane (the sensitizing component of Euxyl K 400, a preservative used in cosmetics). The four chemicals were applied in each of seven different vehicles (acetone: olive oil [4 : 1]; dimethylsulphoxide; methylethylketone; dimethyl formamide; propylene glycol; and both 50 : 50 and 90 : 10 mixtures of ethanol and water). It was found that the vehicle in which a chemical is presented to the epidermis can have a marked effect on sensitizing activity. EC3 values ranged from 0.9 to 4.9% for isoeugenol, from 0.5 to 1.7% for cinnamic aldehyde, from 1.7 to > 10% for dimethylaminopropylamine and from 0.4 to 6.4% for dibromodicyanobutane. These data confirm that the vehicle in which a chemical is encountered on the skin has an important influence on the relative skin sensitizing potency of chemicals and may have a significant impact on the acquisition of allergic contact dermatitis. The data also demonstrate the utility of the LLNA as a method for the prediction of these effects and thus for the development of more accurate risk assessments. Résumé Le test local des ganglions lymphatiques murins (LLNA) peut être utilisé pour déterminer le potentiel relatif de sensibilisation de la peau de produits chimiques, par interpolation des données quantitatives de dose/réponse obtenues. En utilisant cette approche, nous avions démontré précédemment que la matrice vecteur par laquelle un allergène chimique est mis en contact avec la peau peut avoir une influence significative sur le potentiel de sensibilisation. Des estimations d'activité relative sont calculées à partir des doses/réponses de LLNA en fonction de la valeur EC3 dérivée mathématiquement, celle-ci étant la concentration estimée comme induisant un indice de stimulation (IS) de 3. Pour examiner plus avant l'influence du vecteur d'application sur l'activité de sensibilisation, on a utilisé le LLNA pour déterminer l'activité de quatre allergènes de contact humains reconnus: isoeugénol et aldéhyde cinnamique, deux substances chimiques de parfumerie; la 3-diméthylaminopropylamine (une impureté sensibilisante de la cocamidopropyl bétaïne, un tensioactif utilisé dans les gels douches) et le dibromodicyanobutane (le composant sensibilisant de Euxyl K 400, un conservateur utilisé dans les cosmétiques). Les quatre produits chimiques ont été appliqués dans chacun de sept vecteurs différents (acétone: huile d'olive [4: 1]; diméthylsulfoxyde; méthyléthylcétone; diméthylformamide; propy- lène glycol; et deux mélanges 50: 50 et 90: 10 d'éthanol et d'eau). On observe que le vecteur dans lequel le produit chimique est présentéà l'épiderme peut avoir un effet marqué sur l'activité sensibilisatrice. Les valeurs EC3 vont de 0,9 à 4,9 % pour l'isoeugénol, de 0,5 à 1,7 % pour l'aldéhyde cinnamique, de 1,7 à > 10 % pour la diméthylaminopropylamine et de 0,4 à 6,4 % pour le dibromodicyanobutane. Ces données confirment que le vecteur dans lequel un produit chimique est mis en contact avec la peau a une influence importante sur le potentiel relatif de sensibilisation de la peau des produits chimiques, et peut avoir un impact significatif sur l'apparition de dermatite allergique par contact. Les données démontrent aussi l'utilité du LLNA comme méthode de prévision de ces effets et donc pour le développement d'évaluations plus précises des risques. [source] Dependence of the wittig reaction mechanism on the environment and on the substituents at the aldehyde group and at the phosphonium ylideINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 3 2010Giuliano Alagona Abstract The B3P86/6-31G* mechanistic results for the Wittig reaction of acetaldehyde, CH3CHO, in vacuo and in tetrahydrofuran (THF) solution in the IEF-PCM framework, with an unsubstituted trimethylphosphonium or triphenylphosphonium ylide, that is Me3PCH2 or Ph3PCH2, have been compared to those recently obtained at the same levels for the reaction of Ph3PCH2 with a bulky chiral aldehyde, (2S,3R)-2,4-dimethyl-3-pyrrol-1-yl-pentanal [TCA (DOI: 10.1007/s00214-009-0521-4)], here named sys for short. The two model systems show distinct, but similar, behaviors that however differ from the large system one. In particular, betaine-type intermediates are not located in vacuo when Me3PCH2 is used, while only a gauche betaine is obtained using Ph3PCH2; the relevant barriers are anyway smaller than those found for sys. Conversely, in THF, the concerted and stepwise mechanisms are both represented and show TS1/TSb barriers, which are negligibly small for sys. Thus, in contrast to assessed literature, models with methyl groups in place of phenyl rings and branched aldehyde chains show a different behavior from realistic systems and prevent inferring general rules from their use, suggesting to resort to Ph3PCH2 whose results in vacuo and in THF are closer to sys. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 [source] Gene response elements, genetic polymorphisms and epigenetics influence the human dietary requirement for cholineIUBMB LIFE, Issue 6 2007Steven H. Zeisel Abstract Recent progress in the understanding of the human dietary requirement for choline highlights the importance of genetic variation and epigenetics in human nutrient requirements. Choline is a major dietary source of methyl-groups (one of choline's metabolites, betaine, participates in the methylation of homocysteine to form methionine); also choline is needed for the biosynthesis of cell membranes, bioactive phospholipids and the neurotransmitter acetylcholine. A recommended dietary intake for choline in humans was set in 1998, and a portion of the choline requirement can be met via endogenous de novo synthesis of phosphatidylcholine catalyzed by phosphatidylethanolamine N-methyltransferase (PEMT) in the liver. Though many foods contain choline, many humans do not get enough in their diets. When deprived of dietary choline, most adult men and postmenopausal women developed signs of organ dysfunction (fatty liver, liver or muscle cell damage, and reduces the capacity to handle a methionine load, resulting in elevated homocysteine). However, only a portion of premenopausal women developed such problems. The difference in requirement occurs because estrogen induces expression of the PEMT gene and allows premenopausal women to make more of their needed choline endogenously. In addition, there is significant variation in the dietary requirement for choline that can be explained by common polymorphisms in genes of choline and folate metabolism. Choline is critical during fetal development, when it alters DNA methylation and thereby influences neural precursor cell proliferation and apoptosis. This results in long term alterations in brain structure and function, specifically memory function. IUBMB Life, 59: 380 - 387, 2007 [source] Ectoines as compatible solutes and carbon and energy sources for the halophilic bacterium Chromohalobacter salexigensJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2006C. Vargas Abstract Aims:, To investigate the catabolism of ectoine and hydroxyectoine, which are the major compatible solutes synthesized by Chromohalobacter salexigens. Methods and Results:, Growth curves performed in M63 minimal medium with low (0·75 mol l,1 NaCl), optimal (1·5 mol l,1 NaCl) or high (2·5 mol l,1 NaCl) salinity revealed that betaine and ectoines were used as substrate for growth at optimal and high salt. Ectoine transport was maximal at optimal salinity, and showed 3- and 1·5-fold lower values at low and high salinity respectively. The salt-sensitive ectA mutant CHR62 showed an ectoine transport rate 6·8-fold higher than that of the wild type. Incubation of C. salexigens in a mixture of glucose and ectoine resulted in a biphasic growth pattern. However, CO2 production due to ectoine catabolism was lower, but not completely abolished, in the presence of glucose. When used as the sole carbon source, glycine betaine effectively inhibited ectoine and hydroxyectoine synthesis at any salinity. Conclusions:, The catabolic pathways for ectoine and hydroxyectoine in C. salexigens operate at optimal and high (although less efficiently) salinity. Endogenous ectoine(s) may repress its own transport. Ectoine utilization was only partially repressed by glucose. Betaine, when used as carbon source, suppresses synthesis of ectoines even under high osmolarity conditions. Significance and Impact of the Study:, This study is a previous step to the subsequent isolation and manipulation of the catabolic genes, so as to generate strains with enhanced production of ectoine and hydroxyectoine. [source] OCTN3: A Na+ -independent L -carnitine transporter in enterocytes basolateral membraneJOURNAL OF CELLULAR PHYSIOLOGY, Issue 3 2005J.M. Durán L -carnitine transport has been measured in enterocytes and basolateral membrane vesicles (BLMV) isolated from chicken intestinal epithelia. In the nominally Na+ -free conditions chicken enterocytes take up L -carnitine until the cell to medium L -carnitine ratio is 1. This uptake was inhibited by L -carnitine, D -carnitine, ,-butyrobetaine, acetylcarnitine, tetraethylammonium (TEA), and betaine. L - 3H-carnitine uptake into BLMV showed no overshoot, and it was (i) Na+ -independent, (ii) trans-stimulated by intravesicular L -carnitine, and (iii) cis-inhibited by TEA and cold L -carnitine. L - 3H-carnitine efflux from L - 3H-carnitine preloaded enterocytes was also Na+ -independent, and trans-stimulated by L -carnitine, D -carnitine, ,-butyrobetaine, acetylcarnitine, TEA, and betaine. Both, uptake and efflux of L -carnitine were inhibited by verapamil and unaffected by either extracellular pH or palmitoyl- L -carnitine. RT-PCR with specific primers for the mouse OCTN3 transporter revealed the existence of OCTN3 mRNA in mouse intestine, which was confirmed by in situ hybridization studies. Immunohystochemical analysis showed that OCTN3 protein was mainly associated with the basolateral membrane of rat and chicken enterocytes, whereas OCTN2 was detected at the apical membrane. In conclusion, the results demonstrate for the first time that (i) mammalian small intestine expresses OCTN3 mRNA along the villus and (ii) that OCTN3 protein is located in the basolateral membrane. They also suggest that OCTN3 could mediate the passive, Na+ and pH-independent L -carnitine transport activity measured in the three experimental conditions. © 2004 Wiley-Liss, Inc. [source] Safety and effectiveness of topical dry mouth products containing olive oil, betaine, and xylitol in reducing xerostomia for polypharmacy-induced dry mouthJOURNAL OF ORAL REHABILITATION, Issue 10 2007J. A. SHIP summary, Polypharmacy is a common cause of salivary hypofunction, producing symptoms of dry mouth or xerostomia, especially among older populations. As the number of older people continues to increase, polypharmacy-induced salivary hypofunction is becoming an increasing problem. Many over-the-counter products are available for relieving symptoms of dry mouth, but few have been tested in controlled clinical investigations. The purpose of this investigation was to evaluate the safety and efficacy of a group of topical dry mouth products (toothpaste, mouth rinse, mouth spray and gel) containing olive oil, betaine and xylitol. Forty adults were entered into this single-blinded, open-label, cross-over clinical study and 39 completed all the visits. Subjects were randomly assigned at baseline to using the novel topical dry mouth products daily for 1 week, or to maintain their normal dry mouth routine care. After 1 week, they were crossed over to the other dry mouth regimen. The results demonstrated that the use of the novel topical dry mouth products increased significantly unstimulated whole salivary flow rates, reduced complaints of xerostomia and improved xerostomia-associated quality of life. No clinically significant adverse events were observed. These data suggest that the daily use of topical dry mouth products containing olive oil, betaine and xylitol is safe and effective in relieving symptoms of dry mouth in a population with polypharmacy-induced xerostomia. [source] Betaine Protects Chronic Alcohol and ,-3 PUFA-Mediated Down-Regulations of PON1 Gene, Serum PON1 and Homocysteine Thiolactonase Activities With Restoration of Liver GSHALCOHOLISM, Issue 3 2010Ravi Varatharajalu Background:, Paraoxonase (PON1) is an antioxidant enzyme that prevents LDL oxidation as well as detoxifies homocysteine thiolactone (HCTL), both of which can cause atherosclerosis. Chronic alcohol (ETOH) and high ,-3 polyunsaturated fatty acids (,-3 PUFA) consumption may affect PON1 status presumably via reactive oxygen species by depleting liver glutathione (GSH), whereas betaine may counter their effects. Therefore, we investigated the influence of ETOH, ,-3 PUFA, and betaine on liver GSH, PON1 expression, lipid score, as well as serum PON1 and HCTLase activities. Methods:, Experimental rats belonging to various dietary groups were pair-fed with Lieber-DeCarli low (2.8% the dietary calories as ,3-fatty acids) and high (13.8% the dietary calories as ,3-fatty acids) menhaden fish alcohol-liquid diets with and without betaine (10 g/l diet) for 8 weeks after which liver PON1 mRNA, GSH, lipid score, and serum PON1, HCTLase, and ALT activities were measured. Results:, High ,-3 PUFA decreased liver PON1 mRNA expression, serum PON1, and HCTLase activity by 23% (p < 0.01), 20% (p < 0.05), and 28% (p < 0.05), respectively compared to the low ,-3 PUFA group. ETOH decreased PON1 mRNA expression by 25 and 30% (p < 0.01) with concomitant 27% (p < 0.05) and 38% (p < 0.01), decrease in liver GSH levels in low and high ,-3 PUFA groups, respectively. Correspondingly, serum PON1 activity decreased by 23% (p < 0.05) and 58% (p < 0.01) while serum HCTLase activity decreased by 25% (p < 0.05) and 59% (p < 0.01) in the low and high ,-3 PUFA ETOH groups, respectively. Betaine restored liver PON1 mRNA expressions in low and high ,-3 PUFA ETOH groups with parallel restorations of PON1 activity and liver GSH. Concomitantly, betaine reduced hepatosteatosis accompanied by alleviation of liver injury caused by chronic alcohol and high ,-3 PUFA. Conclusions:, Based on these results, we conclude that dietary betaine not only atheroprotective by restoring liver GSH that quenches free radicals, but also may alleviate liver injury by reducing hepatosteatosis. [source] Molecular Mechanisms of Alcoholic Fatty LiverALCOHOLISM, Issue 2 2009Vishnudutt Purohit Alcoholic fatty liver is a potentially pathologic condition which can progress to steatohepatitis, fibrosis, and cirrhosis if alcohol consumption is continued. Alcohol exposure may induce fatty liver by increasing NADH/NAD+ ratio, increasing sterol regulatory element-binding protein-1 (SREBP-1) activity, decreasing peroxisome proliferator-activated receptor-, (PPAR-,) activity, and increasing complement C3 hepatic levels. Alcohol may increase SREBP-1 activity by decreasing the activities of AMP-activated protein kinase and sirtuin-1. Tumor necrosis factor-, (TNF-,) produced in response to alcohol exposure may cause fatty liver by up-regulating SREBP-1 activity, whereas betaine and pioglitazone may attenuate fatty liver by down-regulating SREBP-1 activity. PPAR-, agonists have potentials to attenuate alcoholic fatty liver. Adiponectin and interleukin-6 may attenuate alcoholic fatty liver by up-regulating PPAR-, and insulin signaling pathways while down-regulating SREBP-1 activity and suppressing TNF-, production. Recent studies show that paracrine activation of hepatic cannabinoid receptor 1 by hepatic stellate cell-derived endocannabinoids also contributes to the development of alcoholic fatty liver. Furthermore, oxidative modifications and inactivation of the enzymes involved in the mitochondrial and/or peroxisomal ,-oxidation of fatty acids could contribute to fat accumulation in the liver. [source] Vibrational spectra and quantum chemical calculations of uracilyl,pyridinium mesomeric betaineJOURNAL OF RAMAN SPECTROSCOPY, Issue 11 2007A. Schmidt Abstract Modified nucleobases (MNs) are promising molecules with potential application in non-linear optic (NLO) and drug design against a wide number of diseases. In the present paper we report studies on a cross-conjugated mesomeric betaine, which can act as a MN, formed by the covalent union of a 4-dimethylamino pyridinium and a uracilyl groups. The molecule thus formed must be presented by a dipolar canonical formulae in which positive and negative charges are delocalized within separated moieties. Quantum chemistry density functional theory (DFT) calculations, at the B3PW91/6-31G** level, and Fourier transform (FT) infrared and Raman spectra of this molecule and its N -deuterated derivative were performed. The calculated structural properties over the ground state optimized structure evidenced a strong separation between the two conjugated systems. Comparison with previous results obtained for the cationic species indicated that N -protonation clearly affects the degree of conjugation. Assignments of the FT-IR and FT-Raman spectra were supported by the DFT wavenumbers, intensities and normal modes, which also evidenced the separation of the two conjugated systems. Significant deviations were found for the stretching force constants of the inter-ring and the uracilyl skeletal bonds when comparing this molecule with its N -protonated species. Copyright © 2007 John Wiley & Sons, Ltd. [source] Periocular dermatitis: a report of 401 patientsJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 2 2009E Temesvári Abstract Background, Periocular contact dermatitis may appear as contact conjunctivitis, contact allergic and/or irritative eyelid and periorbital dermatitis, or a combination of these symptoms. The clinical symptoms may be induced by several environmental and therapeutic contact allergens. Objectives, The aim of the present study was to map the eliciting contact allergens in 401 patients with periocular dermatitis (PD) by patch testing with environmental and ophthalmic contact allergens. Methods, Following the methodics of international requirements, 401 patients were tested with contact allergens of the standard environmental series, 133 of 401 patients with the Brial ophthalmic basic and supplementary series as well. Results, Contact hypersensitivity was detected in 34.4% of the patients. Highest prevalence was seen in cases of PD without other symptoms (51.18%), in patients of PD associated with ophthalmic complaints (OC; 30.4%), and PD associated with atopic dermatitis (AD; 27.9%). In the subgroup of PD associated with seborrhoea (S) and rosacea (R), contact hypersensitivity was confirmed in 17.6%. Most frequent sensitisers were nickel sulphate (in 8.9% of the tested 401 patients), fragrance mix I (4.5%), balsam of Peru (4.0%), paraphenylendiamine (PPD) (3.7%), and thiomersal (3.5%). By testing ophthalmic allergens, contact hypersensitivity was observed in nine patients (6.7% of the tested 133 patients). The most common confirmed ophthalmic allergens were cocamidopropyl betaine, idoxuridine, phenylephrine hydrochloride, Na chromoglycinate, and papaine. Limitations, Patients with symptoms of PD were tested from 1996 to 2006. Conclusions, The occurence of contact hypersensitivity in PD patients was in present study 34.4%. A relatively high occurence was seen in cases of PD without other symptoms, in PD + OC and in PD + AD patients. The predominance of environmental contact allergens was remarkable: most frequent sensitizers were nickel sulphate, fragrance mix I, balsam of Peru, thiomersal, and PPD. The prevalence of contact hypersensitivity to ophthalmic allergens did not exceed l.5%. Conflicts of interest None declared [source] Seasonal patterns of sucrose concentration in relation to other quality parameters of sugar beet (Beta vulgaris L.)JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 1 2006Christine Kenter Abstract The chemical composition of sugar beet is the most important parameter affecting its processing. Sugar factories require beet with high concentrations of sucrose and low concentrations of melassigenic substances to maximise the amount of extractable sugar. In order to plan the processing campaign, forecasts of root and sugar yield by prediction models are possible but there are no means to predict the technical quality of the beet. In the present study, the seasonal development and physiological relationships of different parameters of sugar beet quality were analysed. In order to estimate possibilities for quality forecasts, the concentrations of beet quality variables in October were correlated with corresponding quality measurements in late summer and to weather variables during the growing season by linear regressions. In 2000 and 2001, 27 field trials were conducted on commercial farm fields in all sugar beet growing areas in Germany. From June to October, sequential samples were taken every 4 weeks and the concentrations of sucrose, potassium, sodium, total soluble nitrogen, ,-amino nitrogen, nitrate, betaine, reducing sugars and marc in the beet were determined. The sucrose concentration increased progressively until the final harvest date in autumn, whereas the concentrations of the melassigenic substances decreased markedly until late summer and remained fairly constant as the season progressed. Marc concentration was the most stable of the parameters analysed. The sucrose concentration was positively correlated with the concentrations of dry matter, betaine and marc, but negatively with nitrate concentration and leaf yield throughout the season. The correlation between the concentrations of sucrose and nitrogenous compounds measured in summer and their final concentrations in autumn was rather weak. However, it was close for potassium, sodium and marc and a satisfactory prediction of their final concentrations was possible by the end of August. Based on weather data, beet quality was not predictable. Therefore, it seems to be difficult to integrate beet quality parameters into prediction models. Copyright © 2005 Society of Chemical Industry [source] Marc concentration of sugar beet (Beta vulgaris L) in relation to sucrose storageJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2005Christa M Hoffmann Abstract Pulp as a feed stuff produced in the sugar factory is estimated by the marc concentration in sugar beet, which consists of the insoluble cell wall compounds. To identify factors affecting level and development of marc concentration during the growing season, several field trials and pot experiments were carried out in 2000, 2001 and 2002. The results show that marc concentration decreased until 100 days after sowing, but then did not change markedly until October, when it ranged between 34 and 45 g kg,1 beet. Marc concentration was affected more by site and variety than by year. Differences in marc concentration were already established very early in the season (65 days after sowing). This was attributed to the formation of cambial rings and parenchyma cells in the root during this period, which determine sucrose storage. There was a positive correlation between marc and dry matter, sucrose and betaine, but a negative correlation to root yield and amino N. Marc concentration was about 10% lower than reported in the past, which is supposed to be due to a change in the optimal cell volume for sucrose storage and the cell wall thickness of new sugar beet varieties. Copyright © 2004 Society of Chemical Industry [source] | |||||||||||||||||||||||||||||||